1. Field of the Invention
The present invention relates to a technology to prevent unauthenticated viewing even when a Secure Micro (SM) client is leaked.
2. Description of Related Art
When users desire to watch a specific program, a Conditional Access System (CAS) in cable networks determines whether to provide a service based on a user authentication and enables only an approved user to receive the program.
In a CAS in an initial stage, each manufacturing company uses standards different from each other, and thus a CAS is not compatible with other devices excluding a device of a particular company. Accordingly, a broadcasting service provider is required to directly provide a receiving terminal to a subscriber, which imposes a heavy burden on a broadcasting service provider and causes a difficulty in updating a CAS.
OpenCable has provided a standard separating a Conditional Access module from a subscriber terminal to overcome such a disadvantage, that is, to prevent a monopoly of manufacturing company, boost competition, and cause a decline in a product price. Accordingly, a CAS separated from a subscriber terminal is standardized as a cable card of a Personal Computer Memory Card International Association (PCMCIA) card type. Also, a broadcasting service provider provides a subscriber with only a cable card without lending a terminal to a subscriber, and thereby may provide a fee-based broadcasting service. However, an expected result of OpenCable has not been achieved due to an increase in a cable card price and management cost as well as failure in a retail market of terminals.
In such a circumstance, a technology related to a downloadable CAS (DCAS) is provided. The DCAS downloads a conditional access software to a subscriber terminal without a separate hardware conditional access module, and thereby enables a fee-based broadcasting service to be provided.
In a DCAS, a Secure Micro (SM) client may be downloaded and installed in an SM of a host. The SM client is required to be securely managed. When the SM client is leaked, a service provider may be damaged. Accordingly, technologies that may prevent a service from being used without authorization when an SM client is leaked are required.